Cerebellar abnormality in autism: a nonspecific effect of early brain damage?

Cerebellum may be a common site of developmental abnormalities due to its protracted course of maturation. Recent studies have implicated morphological deviations of the cerebellum as responsible for specific behavioral and cognitive manifestations of autism. We investigated neuropsychology and quantitative MRI of the cerebellum in both high functioning subjects with autism and survivors of childhood leukemia treated with radiation and intrathecal chemotherapy. The results of neuropsychological testing revealed different patterns of cognitive deficits for the two groups, while the abnormal cerebellar morphology was similar for both groups. Since it is suggested that the cerebellum contributes to motor-attentional subsystems, the present data provide support for a cerebellar role in the governance of higher cognitive functions, found to be abnormal in both groups. However, the abnormal macromorphology of the cerebellar vermis described here appears to be non-specific to autism.